5,6,7,7a-tetrahydro-4H-1-benzofuran-2-one

2,4-bis(triphenyl-λ⁵-phosphanylidene)cyclobutane-1,3-dione

5-methoxy-8-methyl-2,6-dioxo-2H,6H-benzo<1,2-b:5,4-b'>dipyran

三苯基氧化膦

10-bromo-5-methoxy-8-methylpyrano[3,2-g]chromene-2,6-dione